Added another Junit test to see if I can find the error in which
the leading slash is not put into the final URLs of the generated
artifacts.
Added a test for FingerprintMojo.generateTargetFilename()
Made the getExtension method public instead of private so it is
available for testing.

Added some tests for FingerprintMojo.getExtension().
Made the findPagesToFilter method public instead of private so it is
available for testing.

Added some tests for FingerprintMojo.findPagesToFilter().
Stubbed out the rest of the test methods.  We likely won't use
all of them, but I'm putting them in for test coverage.  I'm still
trying to find the issue with the missing leading slash on fingerprinted
URLs in the processed pages.
This enables us to run the execute() method in a JUnit test.
I was finally able to reproduce the issue in testing.  That
way I can run this in debug and figure out why the leading
slash is not being put into referenced files after the fingerprint
URL is substituted.

Added more configuration to the JUnit setup method to set private
fields in the fingerprintMojo itself.  We needed to set the sourceDirectory
and outputDirectory.

Added a sample URL to run through the fingerprinting process in  the
testing dummy file.  Also added the favicon.ico file to have something to
fingerprint.
Added JUnit test run artifact to the .gitignore file.
Fixed error in the ignore reference for .gitignore.
Fixed the JSTL Pattern matching.  href is excluded and absolute
paths are included.

Added debug statements for the JUnit tests so you can see the
Matcher groupings.

Updated the tests to properly test the new URL matching.